exo·​sphere | \ˈek-sō-ˌsfir \

Definition of exosphere 

: the outer fringe region of the atmosphere of the earth or a celestial body (such as a planet)

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Other Words from exosphere

exospheric \ ˌek-​sō-​ˈsfir-​ik , -​ˈsfer-​ \ adjective

Examples of exosphere in a Sentence

Recent Examples on the Web

Because nitrogen is a volatile chemical, some of it sublimates and gives Pluto a tenuous atmosphere still thick enough to be more than an exosphere. John Wenz, Popular Mechanics, "Here's What We Know About Pluto So Far," 17 July 2015 The spacecraft has two spectrometers that will be analyzing the exosphere. Joe Pappalardo, Popular Mechanics, "4 More Hurdles the LADEE Moon Mission Must Clear," 9 Sep. 2013 Team Unsullied seemed poised for a predictable victory, when suddenly — his square jawline visible from the exosphere — along came dependable ol’ Jaime Lannister, sacking Highgarden and laying waste to Dany’s plans at the last minute. Anna Silman, The Cut, "I’m Rooting for the Lannisters," 4 Aug. 2017 Giant Steps set a new benchmark for virtuosity and harmonic complexity, a manned probe into jazz’s exosphere. Julian Sancton, Billboard, "Remembering Jazz's Greatest Year With the Living Legends of 1959," 5 May 2017 And charged particles in the exosphere can be carried around and away from the planet by the magnetic field. Lisa Grossman, WIRED, "Mercury Flyby Maps New Territory," 15 July 2010

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'exosphere.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of exosphere

1949, in the meaning defined above

History and Etymology for exosphere

exo- + -sphere

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Time Traveler for exosphere

The first known use of exosphere was in 1949

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More Definitions for exosphere


exo·​sphere | \ˈek-sō-ˌsfir \

Kids Definition of exosphere

: the outermost region of the atmosphere

More from Merriam-Webster on exosphere

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Britannica.com: Encyclopedia article about exosphere

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a private place of worship

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